The present invention relates to a printing apparatus having a power saving function (sleep mode) for suppressing power consumption in a non-printing state, a system having the same, and a method of controlling the printing apparatus.
In recent years, printing apparatuses of this type, e.g., page printers represented by laser beam printers have become rapidly widespread.
Generally, an apparatus of this type is constituted by a printer controller for receiving printing data to generate a printing image and at the same time controlling the entire apparatus, and a printer engine for actually performing printing. Since the printer engine has a thermal fixing unit, the power consumption is undesirably increased.
For this reason, in a printing standby state, in other words, when a predetermined period of time has elapsed after supply of printing data from a host unit (e.g., host computer) is cut off, power to the printer engine, particularly to the thermal fixing unit is stopped, thereby appropriately suppressing the power consumption. That is, this printer has a sleep mode (or power save mode).
Setting and canceling of the sleep mode are controlled by the printer controller (CPU in the printer controller). More specifically, upon power-on, or when a predetermined period of time has elapsed after completion of printing processing, and no further printing data is received, power supply to the printer engine is stopped. If printing data is received in the sleep mode, power supply to the printer engine is resumed.
Although the power consumption can be surely reduced in the sleep mode as compared to an actual printing mode, power supply to the printer controller never stops. Additionally, the CPU and various circuits requiring a large power consumption are connected to the printer controller through buses. Taking these factors into consideration, no sufficient power saving effect can be obtained yet.